Objective To evaluate the diagnostic value of coronary CT angiography (CTA) with 64-detector Spiral CT for the detection of coronary in-stent restenosis (ISR). Methods A total of 41 consecutive patients with previous cononary stent implantation with 82 stents were included in this study. All the patients were performed by 64- detector Spiral CT for CTA and conventional coronary angiography (CAG). The later is the "gold standard" for the diagnosis，and if the degree of stenosis ≥50% indicate the present of significant ISR, and to evaluate the sensitivity and specificity, and analyze the factors affecting image quality of CTA. Results Ten ISRs were diagnosised by CAG in the 82 stents, 14 stents could not be evaluated by CTA because of poor image quality. Of 68 stents which could be assessed by CTA, six ISRs were detected by CAG, and seven by CTA, including two false positive, one false negative.In evaluable stents, diagnostic sensitivity, specificity, positive predictive value and negative predictive value of ISR with CTA were 83.3%, 96.8%, 71.4% and 98.4% ,and the difference was no statistically significant (p＞0.05) compared with CAG. In 68 evaluable stents, patents with the heart rate <70 beats per minute (bpm) were in 65 stents (95.6%), stent diameter ≥ 3.0 mm in 54 stents (79.4%), and stent wall thickness <140 μm in 53 stents (77.9%) . 14 stents were unevaluable, of which, 12 stents (85.7%) in patients with heart rate≥70 bpm and 12 in stent diameter <3.0 mm, 13 stents (92.9%) with wall thickness ≥140 μm. Conclusion 64-detector Spiral CT Coronary Angiography can evaluate in-stent restenosis of coronary artery accurately, the patients with slow heart rate, thin-walled and large diameter stent can be better assessed.